Sewing machine irons

If the irons are not labeled (or name is not cast in them), how do you know what machine they will fit?

The reason I ask is that I've run into two sets of irons the last few days that meet that criteria. The wood is shot, the machine is gone and all you really have is the irons. I don't collect or use treadle machines, but if I ran into a desirable set, I would consider buying them.

Kelsie, treadles are so readily found, the idea of a 'build a treadle' (-machine) from scratch boggles my mind
These are the parts you'd need, and I'm guessing they aren't generic? Plus all the ball bearings... If it is readily possible, someone here will set me straight.

I'm not a fan of repurposing working machines, but if I found a set of irons on their lonely and reasonable I'd grab them up and make a table.

At the time, there were several companies that made treadles, so sometimes you'll see the same irons used with different tops for different machines.

Some of the bigger companies (like Singer) made their own cabinets and treadles.

So don't worry about the irons, look at the opening, hinge spacing and hinge type.

I've taken a Singer parlor cabinet and modified it so I could set other machines in it. The opening in the table is standard, and I have bases for the machines and the machine sits on the base in a way so the belt will line up correctly. Some machines the belt to the inside of the flywheel, and some to the outside and that makes a big different in where the machine needs to sit.

My name is Cathy - and I'm addicted to old sewing machines and their attachments.

I would like the best to find a 'matched pair' in a parlour cabinet. I have seen pictures of some neat ones but I have not seen any irons in the flesh and I have been keeping my eyes open since last summer.
bkay were these irons expensive that you saw?

My BIL had one set. I didn't look "under the hood", but he said the machine was missing and that everything there was missing. Someone gave it to him. (The wheel moved in response to "treadling" it.)He said he thought he might put his grandmother's sewing machine in it. I've not seen his grandmother's machine, but I understand it's in one of those wooden round top Singer cases. As I understand it, the machine is in storage.

The other set was in an estate sale. The top was close to rotted out, but the irons were not rusted. They moved in response to "treadling" it.